Chapter 19 - Review Questions

27/10/2010 01:10

1.How do
toxicologists investigate hazardous chemicals? How is this information
disseminated to heal practitioners and the public? (pg. 486)

Toxicologists investigate the potential of certain
chemicals to cause human health problems by conducting test (on animals) to
link the dose (the concentration of the chemical multiplied by the length of
time over which exposure occurs) with the response (acute or chronic effects).

Data on toxic chemicals are made available to health
practitioners and the public via a number of sources, including: the National
Toxicology Program (NTP), Chemical Repository and the National Institute of
Environment Health Sciences (NIEHS). The EPA also makes available data on toxic
chemicals in its Integrated Risk Information System (IRIS). All of these
sources are available on the Internet.

2.What four
categories are used to define hazardous chemicals? (pg. 486 -at the end of the
page-)

HM are extremely toxic; as ions or in certain compounds,
they are soluble in water and many be readily absorbed into the body
(bioaccumulation and biomagnification), where they tend to combine with and
inhibit the functioning of particular vital enzymes.

These compounds are toxic because they are often readily
absorbed into the body (bioaccumulation and biomagnification) where they
interact with particular enzymes, but their nonbiodegradability prevents them
from being broken down or processed further. When ingested in large amounts the
effect may be acute poisoning or death. In small amounts over large periods of
time they can cause mutations, cancer or birth defects.

5.What are
the “dirty dozen” POPs (persistent organic pollutants)? Why are they on a list?
(pg. 489)

They are halogenated hydrocarbons (organic compounds in
which one or more of the hydrogen atoms have been replaced by atoms of
chlorine, bromine, fluorine or iodine -these elements are classed as halogens,
hence the name-). Examples of their use include: plastics (polyvinyl chloride),
pesticides (DDT, Kepone, and mirex), solvents (carbon tetrachlorophenol and
tetrachloroethylene), electrical insulation (polycholrinated biphenyls), etc.

They are on a list because all are toxic to some extents,
and most are known animal carcinogens (cancer causing) and suspected of being
endocrine disruptors at very low levels.

It was common practice to exhaust all combustion fumes up
smoke-stacks, vent all evaporating materials and solvents into the air, and
flush all waste liquids and contaminated wash water into sewer systems or
directly into natural waterways.

7.What two
laws pertaining to the disposal of hazardous wastes were passed in the early
1970s? Describe how the passage of the laws shifted pollution form one part of
the environment to another. (pg. 491)

The Clean Water Act
of 1970 and Clean Water Act of 1972
were passed to reduce the worsening pollution problem of air and waterways.
These acts set standard for allowable emissions into air and water and
timetables for reaching those standards.

Their passage in the early 1970s left an enormous loophole.
If you can't vent waste into the atmosphere or flush them into waterways, what
do you do with them? Industry turned to land disposal, which was essentially
unregulated at the time. In retrospective, the Clean Air and Clean Water acts,
improved air and water quality, but succeeded in transferring pollutants from
one part of the environment to another.

8.Describe
three methods of land disposal that were used in the 1970s. How has their use
changed over time? (pg. 492 - 494)

Deep
well injection:

·Involve drilling a bore hole thousands of feet
below groundwater into a porous geological formation of brine. A well consists
of concentric pipes and casing that isolate the wastes as they are injected and
the well is sealed at the bottom to prevent wastes from backing up.

·The EPA requires this wells to be made in
geological stable regions to avoid leakages.

·The use of deep well injections has declined
over the years.

Surface
impoundments:

·Are simple excavated depressions (ponds) into
which liquid wastes are drained and held.

·Least expensive and hence most widely used way
to dispose of large amounts of water carrying relatively small amounts of
chemical wastes.

·Inadequate sealing of the bottom of the pond may
allow waste to percolate into groundwater, storms may cause overflow and
volatile materials can evaporate to the atmosphere.

Landfills:

·[External definition: method of hazardous and
non-hazardous waste disposal. Non-hazardous materials are spread in layers,
compacted to the smallest practical volume, and buried. Hazardous material have
to be treated in accordance with their chemical and physical characteristics
(regulated by EPA), before disposal in specific (licensed) landfills.]

·Changed from being unregulated to heavily
regulated by the EPA through waste treatment standards.

9.What law
was passed to cope with the problem of abandoned hazardous-waste sites? What
are the main features of the legislation? (pg. 496)

The Comprehensive
Environmental Response, Compensation and Liability Act of 1980 (CERCLA) was
passed, also known as Superfund.

Through tax on chemical raw material, this legislation
provides a trust fund for:

·the identification of abandoned chemical waste
sites,

·protection of groundwater near the site

·remediation of groundwater (if contaminated)

·cleanup of the site

Congress has refused to renew the tax on industry, leaving
US taxpayers with the continuing cleanup bill.

·Tanks have to be upgraded or replaced if the
they are only made of steel.

·LUST is financed by the 0.1-cent-per-gallon tax.

11.What law
was passed to ensure the safe land disposal of hazardous wastes? What are the
main features of the legislation? (pg. 501)

The Resource
Conservation and Recovery Act (RCRA) was passed. It has three main
features:

1.It requires
all disposal facilities be sanction by permit. The permitting
process requires that the facilities have all the required safety features.

2.Toxic
wastes destined for landfills
have to be pretreated to convert them to form that will not leach
(e.g. biodegradation or incineration).

3.Cradle to
grave tracking of all hazardous wastes. The [waste] generator must fill out a
form detailing the exact kinds and amounts of waste. Persons transporting the
waste and those operating the disposal facility must each sign the form,
vouching that the amounts of waste transferred are accurate.

12.What laws
exists to protect the public against exposures resulting from hazardous
chemical accidents? What are the main features of the legislation? (pg. 520 -
503)

Department
of Transportation Regulations (DOT): Specify the kinds of containers and methods of packaging
to be used in the transport of various hazardous materials. They also require
that every individual container and the outside of a truck or railcar to carry
a standard placard identifying the hazard of the material inside.

Worker
Protection – OSHA ACT and the “Worker's Right to Know”: Basically the law requires businesses,
industries and laboratories to make available both information regarding
hazardous materials and suitable protective equipment.

Community
Protection and Emergency Preparedness – SARA, Title III: Superfund
Amendments and Reauthorization Act of 1986 (SARA), Title III is better known as Emergency Planning and Community Right-to-know Act (EPCRA).

It requires companies that handle in excess of 5 tons of
any hazardous material to provide a “complete accounting” of storage sites,
feed hoppers, and so on. The information goes to a local emergency planning committee, which has the task of drawing
up scenarios for accidents involving the chemicals on-site and to have a
contingency plan for every case. The committee is mad up representatives of
local fire and police departments, hospitals and other groups that may be
involved in case of emergency.

13.What role
does the Toxic Substances Control Act play in the hazardous waste arena? (pg.
503)

It requires that, before manufacturing a new chemical in
bulk, manufacturers submit a “pre-manufacturing notice” to the EPA in which the
potential environmental and human health impacts of the substance are assessed
(including those which may derive from the ultimate disposal of the chemical).
Depending of the results of the assessment, the EPA may authorize further
testing and will determine the final restrictions on the products use or keep
it of the market all together.

14.Why does
the EPA have an environmental justice program? (pg. 504)

EPA definition: “[environmental justice is] the fair
treatment and meaningful involvement of all people regardless of race, color,
national origin, or income with respect to the development, implementation, and
enforcement of environmental laws, regulations, and policies. Fair treatment
means that no group of people, including racial, ethnic, or socioeconomic
group[s], should bear a disproportionate share of the negative environmental
consequences resulting from industrial, municipal and commercial operations or
the execution of federal, state, local and tribal programs or policies”

The program was started amongst other things, because several
recent studies have shown that, all across the US, waste sites and other
hazardous facilities are more likely to be located in towns and neighborhoods
where most of the residents where non-Caucasian.

15.Describe
the advantages of pollution prevention efforts? (pg. 505)

It involves changing the production process, the materials
used, or both so that harmful pollutants won't be produced in the first place.